Suggestions for finding Beta Testers?

Curious if anyone has any tips or hidden gems as to where I could find a good android community of users willing to beta test apps? I’ve found BetaBound to be the best by far but curious if anyone else has had any luck?

Our app is taking sign ups now and will be launching next week. The app’s premise is to reward users for ad exposures instead of blocking or staying annoyed with them. The app works in the background and knows when you encounter a brands ad we are working with. You are sent rewards and promotions from brands in exchange for seeing their ads.

If anyone here is interested feel free to sign up here: Omni Labs

Thanks and looking forward to hear other tips.